The present invention relates to a biologically active substance and the process for preparing and isolating a therapeutically valuable substance and more particularly, to the biologically active substance having insulin secretion promoting action and the process for preparing a substance obtained from the cultivation of suitable strains of a microorganism, Bordetella pertussis (Phase I or Phase II) in a suitable culture medium, and to the thus obtained substance.
The present inventors have detected in the cells and in their culture medium of Bordetella pertussis known as the pathogen of pertussis, a proteinic substance having the amazing pharmacological activities in promoting the secretion of insulin thus resulting in maintaining the normal blood sugar level in mammals, and which, accordingly, is credited with a high medical utility for treatment and prevention of various kinds of diabetes. The present inventors have also succeeded in isolation and chemical identification of this novel proteinic substance as an insulin secretion potentiating factor and after finding that the proteinic substance demonstrates a prominent activity in promoting the secretion of insulin at an extremely small dose of approximately 0.1 .mu.g/kg body weight, have proved usefulness in treatment and prevention of various kinds of diabetes, and then have attained to the present invention.